One dimension cam tracer for an automatic milling machine

ABSTRACT

Amachine bed is displaced in one plane in response to the pressure of a first stylus upon a first cam surface. Displacement along an axis orthogonal to the plane is in response to the pressure of a second stylus upon a second cam surface which is transmitted via a lever and a gimbal to the first stylus.

United States Patent Whitney 1 July 31, 1973 ONE DIMENSION CAM TRACERFOR AN FOREIGN PATENTS OR APPLICATIONS AUTOMATIC MILLING MACHINE 976,58912/1963 Germanymr. 90/62 R [75] Inventor: Herbert A. Whitney, Windsor,Conn. [73] Assignee: United Aircraft Corporation, East Primary Examineroll weidenfeld Hartford Conn AttorneyLeonard Weiss [22] Filed: May 31,I972 211 Appl. No.: 258,278 [57] ABSTRACT A machine bed is displaced inone plane in response to 52 U.S. c1 90/13 B, 90/62 R the Pressure afirst Stylus a first cam Surface- 51 1m. 01. B23c 1/16 Displacement anaxis the Plan6 is 58 Field of Search 90/13 B 62 R respme to Pressure aSecond Stylus upon a second cam surface which is transmitted via a leverand [56] Reierences Cited 21 gimbal to the first stylus.

UNITED STATES PATENTS 2 Claims, 3 Drawing Figures 2,810,327 10/1957Schmid 90/62 R O E J ONE DIMENSION CAM TRACER FOR AN AUTOMATIC MILLINGMACHINE BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates to machining apparatus and more particularly to animprovement to an'automatic hydro copy miller manufactured by RigidLimited.

2. Description of the Prior Art In the hydro copy miller manufactured byRigid Limited, a machine bed is displaced in response to pressureapplied to a stylus. The stylus is made to traverse a three-dimensionalcam surface whereby desired displacements of the machine bed in an X, Yand Z direction are achieved in accordance with pressure of the camsurface upon the stylus. In the Rigid machine, it is well known that acam which causes a displacement of the machine bed in the Z directionmay coupled an undesired pressure upon the stylus in the X and Ydirection thereby causing an undesired displacement of the machine bed.Accordingly, it is a usual practice to use the hydro copy miller onlywhen very small displacements in the Z direction are required. Machiningwhich requires substantial displacement in the Z direction is performedby another machine, such as a pantograph.

Heretofore, the utility of the hydro copy miller has been limitedbecause accurate displacement of the machine bed in the Z directioncould not be achieved.

SUMMARY OF THE INVENTION The object of the present invention is toprovide a simplified automatic hydro copy miller.

According to the present invention, displacement of a'machine bed in oneplane is in response to the pressure of a first stylus upon a first camsurface representative of the desired displacement of said machine bedin said plane; displacement of said machine bed in a directionorthogonal to said plane is in response to the pressure of a secondstylus upon a second cam surface representative of the desireddisplacement in said orthogonal direction; the pressure of said secondstylus upon said second cam surface is transmitted by a transmissionmeans to said first stylus.

The present invention provides for complex automatic machining in oneoperation which had heretofore been performed in a plurality ofoperations.

Other objects, features and advantages of the present invention willbecome more apparent in the light of the following detailed descriptionof a preferred embodiment thereof as illustrated in the accompanyingdrawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic showing of thepreferred embodiment of the present invention;

FIG. 2 is a top view of a cam in the embodiment shown in FIG. 1; and

FIG. 3 is a top view of the gimbal in the embodiment shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention is animprovement of an automatic hydro copy miller model KA-ZOO manufactured6 Referring now to FIGS. 1 and 2, a tracer stylus 10 (FIG. 1) makescontact with the edge of a cam surface 12 (FIG. 2) of a cam 14. The cam14 is mounted upon a machine bed 15. The bearing pressure of the camsurface 12 upon the stylus 10 (FIG. 1) causes small error rotationsthereof about a pair of mutually orthogonal axes which are orthogonal toa vertical Z axis which is in the direction of an arrow 16. Therotations are transmitted through a transmission member 18 to hydraulicservo valves 20, 22 which cause the drive mechanism of the machine tomove the machine bed 15 in a direction to bring the rotation to a nullbut maintain contact between the stylus 10 and the cam surface 12. Themachine bed 15 is moved by the drive mechanism of the machine to causethe stylus 10 to trace the cam surface 12. Therefore, a stationarycutting tool may be made to cut a workpiece (the cutting tool and theworkpiece are not shown) in accordance with the motion of the machinebed 15.

Pressure of the stylus 10 in the Z direction causes a small errordisplacement thereof which activates a by draulic valve 24, causing acorresponding displacement of the machine bed 15. According to thepresent invention a cam 26 has a cam surface 28 which is representativeof desired displacement of the stylus 10 in the Z direction at everylocation of the stylus 10 along the contour 12 (FIG. 2). Referring toFIGS. l-3, a second stylus 30 is connected through a gimbal 32 and alever 34 to the first stylus 10. The lever 34 and the stylus 10 arerespectively connected to an outer ring 35 and an inner ring 37 of thegimbal 32. An extension 36 of the lever 34 is pivotally connected to apivot 38 to a stationary member 40. Displacement of the stylus 10 alongthe contour 12 causes a corresponding displacement of the stylus 30along the cam surface 28. Pressure in the direction of the Z axis uponthe stylus 30 are transmitted to the first stylus 10 causing acorresponding pressure thereupon in the direction of the Z axis;components of pressure in directions orthogonal to the Z axis are nottransmitted through the gimbal 32 to the stylus 10, therefore the valves20, 22 are not activated by the pressure of the stylus 30 upon the camsurface 28.

Although the invention has been shown and described with respect apreferred embodiment thereof, it should be understood by those skilledin the art that various changes and omissions in the form and detailthereof may be made therein without departing from the spirit and thescope of the invention.

Having thus described a typical embodiment of my invention, that which Iclaim as new and desire to secure by Letters Patent of the United Statesis:

1. In an automatic copy milling machine'where a machine bed is displacedin relation to a cutting tool in accordance with pressure applied to afirst stylus, the improvement comprising:

a first cam connected to said machine bed, said first cam having a firstcam surface in contact with said first stylus, said first cam surfacedefining a pattern in one plane in accordance with the desireddisplacement of the machine bed in a given plane;

a second stylus;

a second cam mounted upon a machine bed, said second cam having a secondcam surface in contact with said second stylus, said second cam surfacerepresentative of the desired displacement of said machine bed in adirection orthogonal to the pattern of said first cam;

2. Apparatus according to claim 1 wherein said transmitting meanscomprise:

a gimbal having an inner ring thereof connected to said first stylus;and

a lever having ends fixedly attached to said second stylus and to anouter ring of said gimbal respectively, said lever being long comparedto displacements of the stylus in the Z direction.

II I I i I!

1. In an automatic copy milling machine where a machine bed is displacedin relation to a cutting tool in accordance with pressure applied to afirst stylus, the improvement comprising: a first cam connected to saidmachine bed, said first cam having a first cam surface in contact withsaid first stylus, said first cam surface defining a pattern in oneplane in accordance with the desired displacement of the machine bed ina given plane; a second stylus; a second cam mounted upon a machine bed,said second cam having a second cam surface in contact with said secondstylus, said second cam surface representative of the desireddisplacement of said machine bed in a direction orthogonal to thepattern of said first cam; means for moving said machine bed to causesaid first and second styluses to continuously contact portions of saidfirst and second cam surfaces, respectively; and means for transmittingdisplacement in the orthogonal direction of said second stylus bycontacting the profile of said second cam surface to said first stylusthereby causing a corresponding displacement of the machine bed in adirection orthogonal to the given plane.
 2. Apparatus according to claim1 wherein said transmitting means comprise: a gimbal having an innerring thereof connected to said first stylus; and a lever having endsfixedly attached to said second stylus and to an outer ring of saidgimbal respectively, said lever being long compared to displacements ofthe stylus in the Z direction.